Hello GitP! I just finished writing a new Cleric subclass, and I'm looking for criticism and suggestions of it. I have not playtested it yet, but plan to do so. Before that, I want to make sure that is is polished. Mechanical feedback about what seems balanced in terms of power levels, compared to other Cleric domains, usability and practical application and just general uniqueness and fun to playness. Feedback about fluff, thematic options and lore are also welcome, but not as needed.

The idea of the class revolves around defbuffing, and control, as well as a bit of ally-buffing. The former two which the base cleric doesn't have that much of. Maybe a little stealth, but I'm a bit iffy on that, as it might step on Trickery domain's toes. Commentary on the reasoning and purpose behind each feature is under the actual features.

Night Domain

The gods of night embody that of which is unknown, slumbering and often terrifying. They can be wildly differing in their motives, but they all have one thing in common. They are the alternate side of human nature, that of which has existed from their birth to their death. They can be everything not in the waking life, and the subconscious, the world of dreams. The night is dark and seemingly empty, lacking the warmth of the day. Gods of this domain include Shar, Tharizdun, Takhisis, Set, and Hel. As well as gods of the stars, moon, underworld and sleep, such as Selune, Celestian, Sehanine Moonbow, Osiris and Hecate.

Night Domain Spells
Cleric Level Spells
1st Sleep, Bane

3rd Darkness, Moonbeam

5th Slow, Fear

7th Evardís Black Tentacles, Greater Invisibility

9th Dream, Hallow

Bonus Proficiencies
When you chiste this doman ay 1st level, you gain proficiency in the stealth skill. Additionally, wearing medium armor does not impose disadvantage on stealth checks.

Blessing of the Night
When you choose this domain at 1st level, You gain darkvision out to a range of 90 feet. If you already have darkvision, the range of it extends by 30 feet.

Channel Divinity: Reach of the Night
Starting at 2nd level, as an action, you can present your holy symbol, and utter a prayer to your deity. Shadows stretch out from you, and up to ten creatures of your choice within a 30 foot radius of you must make a constitution saving throw, or be blinded and have their speed halved. An affected creature can repeat the saving throw at the end of their turn, ending the affect on a success.

Wreathe of Nightmares
Starting at 6th level, as an action, you can touch a willing creature. For one minute, any time a creature hits that creature with a melee attack and is within 5 feet of it, it momentarily suffers a nightmare, and takes psychic damage equal to half your Wisdom modifier rounded up. (Minimum 1) If you apply this to another creature before the duration is up, then it immediately ends on the first creature. The damage increases to your Wisdom modifier at level 17. You can do this an amount of times equal to half your Wisdom modifier rounded up. (Min 1) You regain all uses after a long rest.

Potent Spellcasting.
At level 8th level, you can add your Wisdom modifier to the damage you deal with any cleric cantrip.

Grasp of Shadows
Starting at 17th level, as an action, you can wrap up to 3 huge or smaller creatures you can see within 60 feet in darkness. They are restrained and blinded. As an action, a creature can make a Dexterity(Acrobatics) or Strength(Athletics) check against your cleric spell save DC and free itself from the effect on a success, dispelling the shadows that held it. You regain the ability to do this after you finish a long rest.

Commentary:

Spells:
Sleep- Fits thematically with the night theme, as night sleeping, etc. Powerful low level knockout spell that can end encounters if done right, and starts off with the debuffing theme, this being an outright stun/knockout. It doesn't scale that well, so after level 5 it's not that useful
Bane- Another debuffing spell, penalizing enemy attacks and saves. While the night cleric isn't based around cursing, this one is tame enough, and already appears on the cleric spell list. Not too mention that as a cleric, you'll probably have higher priority things to concentrate on, like bless, etc.

Darkness- Fits thematically perfectly with the whole 'night' thing. Very powerful tool to limit enemy lines of sight, or put them at a disadvantage, or even force them to move out of the cloud and go somewhere better. Good for battlefield control, though it has to be used carefully to avoid ducking yourself and team.
Moonbeam-Taken from the Druid spell list, this one is a bit of an oddball, a damage dealing spell in a list of debuffing ones. This one is for all the moon gods and goddesses, and is a solid AoE damage dealer over time. Contrasts with the other spell at this level.

Slow-Another debuffing spell, this one is an AoE, and could be pretty useful during a fight.
Fear-The terror of the night has no end... This one is a very debiliating AoE, like slow and can turn the tide of a battle. Not on the cleric spell lists, and expands your options in terms of debuffing, and control.

Evard's black tentacles- Summon these Lovecraftian-esque tentacles to hinder and damage your foes. Another one of the unkown horrors of the night. Another crowd control and debuff spell.
Greater invisibility - great buff for your team. Things that move unseen during the night. A bit of the buffing stuff I mentioned before, and the threat of the unseen and known works thematically.

Dream- Fluffy utility spell that may or may not be useful. The night is the time of dreams, and you can torment your enemies as they sleep.
Hallow- You can create darkness in the hallow here, and it's an area control. I suppose it works, though I don't like this too much.

Bonus Proficiency:
You'll be very stealthy, even when wearing medium armor. Once again, the recurring theme of being out of sight appears. This is just a useful skill that clerics might have a hard time picking up,

Blessing of the Night:
You are at home in the darkness, and its presence does not hinder or impede you. Works thematically obviously, and can turn you into a good scout, along with the previous feature. Night cleric like the dark,

Channel Divinity: Reach of the Night.
Another debuff option you have. Just like the light cleric and their nuking feature. You can exclude allies too. I added the repeating of the save, just so it isn't too powerful. Feels kinda bland though, and I need some help naming it.

Wreathe of Nightmares
Another bit of buff here, this can turn your party tank into a menace. I kept the damage half of wisdom modifier, so until level 17 it will always be 2-3 damage. You also can only have it on one person, and use it a handful of times per long rest, to prevent it from getting too abusable.

Grasp of Shadows
Once again, another debuffing feature, and this lets you restrain and blind things, with no save! And make them waste their action if they want to get out. Quite powerful, but so is every level 17 cleric feature. Long rest means you have to employ it judiciously. Your wreathe of nightmares also gets an upgrade at this level, as I wanted it to scale a little.